1906. J ANATOMY OF THE OPHIDIA. 27 



kidney. These longitudinal parietal vessels are npon the left 

 side of the body. 



(8) As in Eunectes murinus, the left anterior abdominal trunk 

 only is connected with the afferent renal of its side*. The 

 right-hand trunk arises from a plexus on the gut. 



(9) The azygos vein is short and developed on the right side 

 only. 



(10) Attention is called to anatomical differences between the 

 two species of Eimectes, which concern the division of the pancreas 

 and spleen in E. murinus, these organs being in one piece in 

 E. notceiis. 



(2) Some Notes ii^pon the Venous System of Python sebee. 



It might perhaps be supposed that after the apparently 

 exhaustive survey of Jacquart t hardly anything concerning the 

 venous system of Python remained for description. Nevertheless 

 M. Jacquart has not dealt fully with a few points of which the 

 importance was perhaps less apparent at the time when he wrote 

 than at present. Since M. Jacquart's memoir, which is abun- 

 dantly illustrated, nothing concerning the vascular system in this 

 genus has been published except a few notes by myself J in a 

 paper dealing mainly with the arteries of a number of genera of 

 Ophidia. Those notes, however, refer to Python spilotes. My 

 present communication refers, as did the memoir of Jacquart, to 

 Python sebce. 



I have dissected during the past year or two three individvials 

 of this snake, of which one only was specially favour-able for the 

 stud}^ of the venous system, owing to its fresh condition and the 

 turgescence of the veins. It was possible in this individual to 

 follow the smaller branches of the veins with ease, and no injection 

 could have produced so favourable a state of affairs for examining 

 the relations of veins. 



Having so recently studied in detail the anatomy of the venous 

 system of the Anaconda §, my object has been to compare and is 

 to set down the differences and resemblances between these^ two 

 genera of Boidse — types as they are of the two subfamilies, 

 Boinfe and Pythoninas, into which systematists have divided the 

 family. The validity of comparisons having a purely classificatory 

 aim is of course to some extent affected by the undoubted 

 fact that species of the same genus among the Boidae may show 

 rather important differences in their veins, as I have been able 

 to demonstrate in the case of Eryx ||. 



A f event Penal Veins and Posterior Cardinals. — In Amphishcena f 



* It is necessary to emphasise this agreement between two species of the same 

 genus, since in JSryx there are specific differences in this respect between JSryx 

 jacultis and B. conicus, as I have shown (P. Z. S. 1904, vol. ii. p. 119). 



t Ann. Sci. Nat. loc. cit. 



I P. Z. S. 1904, vol. i. p. 362. 



§ See above. II P. Z. S. 1904, vol. ii. p. 107. 



4 P. Z. S. 1905, vol. ii. p. 485. 



